AmerisourceBergen shares rose 15.7 percent in after-hours trading and shares of Walgreens, which has around 13,000 drugstores worldwide, mostly in the United States, were unchanged. Walgreens is valued at $67.82 billion and AmerisourceBergen has a market capitalization of $19.65 billion, according to Thomson Reuters data. A new deal by Walgreens would follow the $69 billion acquisition of health insurer Aetna Inc by drugstore rival CVS Health Corp and would also reflect a move toward vertical consolidation, where members of a supply chain combine.

Walgreens, the biggest U.S. drugstore chain, said on Wednesday it would buy the minority stake from China National Accord Medicines Corp Ltd for about $416 million. The deal comes when the Chinese government has been encouraging private investments and equity from abroad in its healthcare industry. Healthcare expenditure in China is expected to reach $1.1 trillion by 2020, according to an estimate by the U.S. Department of Commerce.